A verbal is a verb that acts like a different part of speech. Infinitives, gerunds, and participles are all types of verbals. An infinitive is a verbal consisting of to + a verb, and it acts like a subject, direct object, subject complement, adjective, or adverb in a sentence.
HeadOn is the brand name of a topical product claimed to relieve headaches. It achieved widespread notoriety in 2006 as a result of a repetitive commercial, consisting only of the tagline HeadOn. Apply directly to the forehead, stated three times in succession.
A blackhead, or open comedo is a wide opening on the skin with a blackened mass of skin debris covering the opening. Despite their name, some blackheads can be yellowish in color. A comedo is a widened hair follicle which is filled with skin debris (keratin squamae), bacteria and oil (sebum).